\documentclass{article}
\usepackage{amssymb,amsmath,amscd,concmath}
\pagestyle{empty}
\begin{document}
\begin{equation*}\overline{=\frac{F(P_3)-3F(P_2)+3F(P_1)-F(P_0)}{\Delta_1P^3};}\,\!\end{equation*}
\end{document}
